426 



Fishery Bulletin 102(3) 



140 



120 



o 

 o 



°. 100 

 o 



~ 80 



C 

 13 

 O 



•2 60 



£ 

 3 

 o 

 £ 40 



< 



20 



-* — prefertllization 

 -o— fertilized 



10 12 14 



Age (years) 



16 



20 



Figure 8 



Separate-lines regressions fitted to absolute fecundity (based on pre- 

 fertilization and fertilized eggs) on age for black rockfish in Oregon. 



estimates for fertilized and prefertilization females were 

 approximately equal. Yolked oocytes from older females 

 were more successful in reaching the developing embryo 

 stage. This may be attributed to higher rates of fertil- 

 ization, greater viability of embryos, or a combination 

 of both in older female black rockfish. Regardless of 

 the mechanism there should have been signs of greater 

 atresia in the ovaries of young fish, which we did not 



observe in our histological preparations. This may have 

 been due to rapid resorption of unfertilized oocytes or 

 an artifact of the fragile nature of fertilized ovaries, 

 which made it difficult to obtain representative histo- 

 logical preparations. Nevertheless, these results sug- 

 gest that fecundity in black rockfish is best described 

 after fertilization, but care must be taken to minimize 

 embryo loss. These results also suggest that current 



